Abstract: A signal transmission system, particularly for television, comprising a nonlinearity precorrection device having a principal channel and a subsidiary channel. The subsidiary channel comprises a nonlinearity product generator with two amplification channels, a linear channel and a nonlinear channel which enable nonlinearity products having a suitable phase to be extracted by the difference of their output signals. The principal channel comprises a circuit formed from two linear channels in parallel whose output signals are added together in an adder. The output signals of the subsidiary channel and the principal channel are added. This precorrection device enables automatic correction of the nonlinearity products to be set up.

Abstract: A power amplifier connection comprises a switching amplifier and a proportional amplifier. The output signal from the switching amplifier and the output signal from the proportional amplifier are supplied to a summation member which, by addition of the two output signals, forms the resultant output signal of the amplifier connection. The switching amplifier is adapted to be controlled in dependence on the input signal of the amplifier connection in such a way that its output signal endeavours to follow the input signal. The proportional amplifier is adapted to be controlled in dependence on the deviation between the input signal and output signal of the amplifier connection.

Abstract: A wide band, feedforward, power amplifier circuit has greater stability when quadrature hybrid devices are used to match the output impedance of the power amplifier with the load.

Abstract: The audio-frequency amplifying device comprises a first class B amplifier, a second class B amplifier, switching means controlled by a control sub-assembly and transmission means applying a signal to the input of the second amplifier. The load is connected to the first amplifier, and to the switching means connecting it either to the output of the second amplifier or to a zero potential middle point.

Abstract: A car-mounted audio equipment of multiamplifier system including a single preamplifier, a plurality of power amplifiers and the corresponding number of differential amplifiers each connected between an output terminal of the preamplifier and an input terminal of each of the power amplifiers comprises a biasing means for biasing at least one of the ground terminals of the power amplifiers to a potential substantially equal to the ground potential when the one terminal is in an open state.

Abstract: A modular amplifier comprising a plurality of modules receives a signal to be amplified and provides an amplified signal through power divider and power combiner circuits which are mirror images of each other. In particular, 2-way Wilkinson hybrid circuits are combined to deliver the input signal by providing a divided signal to each of the amplifier modules. The output of each of the modules is combined by 2-way Wilkinson hybrid circuits to provide the amplified signal output. In order to provide discrete power reduction switching from a full power condition to a reduced power condition, at least one of the inputs to a module is connected to a quarter-wave stub which is selectively grounded and open-circuited to reflect respectively an open circuit and a short circuit condition. In this way, each amplifier module performs similarly in the reduced power output condition as well as in the full power output condition.

Abstract: The present invention relates to a non-linearity compensating circuit for high-frequency amplifiers comprising a branch coupler for dividing the input signal into two components, two high-frequency amplifiers, one operating in the non-linear region, the other operating in the linear region, and each receiving one of the two signal components from said branch coupler, and a signal synthesizing circuit for taking the vectorial sum of the two antiphase signals from the two amplifiers whereby the non-linearity compensating circuit provides an input/output characteristics which is just the opposite of the input/output characteristics of the high-frequency amplifier to be compensated. Basically, the non-linearity compensating circuit according to the present invention does not require long delay lines, variable attenuators or variable phase-shifters of a special design so that the whole circuit can be constructed in a microwave integrated circuit form which has a reduced power loss.

Abstract: This circuit divides power from an input source equally among N different paths, where N is an arbitrary number. These individual path powers can then be amplified separately to take advantage of the full output power ratings for the individual amplifiers, then the outputs from the amplifiers are combined. A combiner circuit, which is the reverse of the divider circuit, then combines the individual powers to a single output. In each of the combiner and divider circuits, the phase angles of the output ports vary from each other by 90 degrees sequentially down the entire chain of N-1 couplers. Each combiner and divider network utilizes N-1 series-connected couplers, preferably interdigitated ones. The interdigitated couplers utilize preselected power division ratios based upon N.

Abstract: A noise suppression device for automobile stereo components having a noist suppression circuit interposed between the output of the audio source and the input of the amplifier section. The suppression circuit has a differential amplifier or an operational amplifier to eliminate noise from the source. In a multi-amplifier system the noise suppression device is interposed between the pre-amplifier and the primary amplifiers.

Abstract: A broadcast transmitter has the outputs of two high-power output stages combined for increased power. For enhanced reliability, two exciters or sources of broadband signals are provided, and a switch couples the signal from the selected exciter to a signal splitter. In the signal splitter, the selected signal is divided into two equal portions, and each portion is coupled to the input of one of the two high-power stages. Two surface acoustic-wave filters are provided for limiting the bandwidth of the signal as transmitted. The filters may have different phase characteristics in the passband. Two or more distortion correction arrangements are provided for predistorting the signal for correcting for differential gain, differential phase or incidental phase distortions arising in the high-power stages.

Abstract: A noise-free electronic switching circuit selects one of a pair of audio input signals in an audio system. Each input signal is connected by separate conductors to a single output terminal. The output terminals of two transistors are respectively connected between each conductor and ground. When a manually-operated switch is switched to a first operating condition, an exponentially increasing and an exponentially decreasing control voltage are respectively applied to the bases of a first and a second transistor. When the actuating switch is switched to a second operating condition, an exponentially decreasing and an exponentially increasing control voltage are respectively applied to the bases of the first and the second transistor. In either operating condition, one transistor is turned on and the other is turned off. Thus, only the selected audio signal is delivered to the output terminal; and the other non-selected audio signal is shorted to ground before reaching the output terminal.

Abstract: An RF amplifier stage of an AM broadcast tuner is disclosed wherein, depending upon the power level of the received input signal, said input signal is amplified by a high gain radio frequency amplifier, or by a low gain radio frequency amplifier, or by a combination of both the high and low gain radio frequency amplifiers at intermediate levels. This system provides wide dynamic range and low distortion in that it prevents amplifier saturation and reduces intermodulation product signal levels.

Abstract: Apparatus for controlling the gains of a pair of gain-matched amplifiers includes means for applying to each amplifier a pilot tone in the form of an exponentially-decaying periodic signal. The apparatus also includes three control loops, one for comparing the output of one amplifier with a reference signal to derive an error signal used to control the amplifier gains when the pilot tone is absent, and a second for controlling the gains when the pilot tone is present. The third loop subtracts the outputs of the two amplifiers and uses the resulting error signal in conjunction with one or other of the signals from the other two loops to control the gain of one of the two amplifiers.

Abstract: Apparatus for reducing the intermodulation noise generated in a chain of amplifiers. The apparatus includes a first phase-shift circuit for at least partially compensating for the phase distortion and phase jumps in the chain and a balancing circuit including a source of compensating noise.The compensating noise is inverted, then added to the original signal to cancel the distortion generated in the chain. In one embodiment, the source of the compensating noise is a series of amplifiers and phase-shift networks which simulate the transmission characteristics of the actual amplifier chain.

Abstract: A circuit for suppressing pulse-shaped interferences in an audio signal caused by scratches on a phonograph disc, comprising a signal processing section connected between an audio frequency input and an audio frequency output, comprising a noise suppressor having a control input; as well as a control signal section connected between the audio frequency input and the control input, said control signal section comprising a first threshold selection circuit connected to the audio frequency input for selecting pulse-shaped signals from the audio signal, followed by a second threshold selection circuit for distinguishing the pulse-shaped signals originating from noise signals from those originating from musical signals.

Abstract: A synchro buffer amplifier is provided which uses two matched amplifiers respectively connected to the primary windings of two transformers. Two input leads are respectively connected to the inputs of the two amplifiers and a third input lead is grounded. The secondary windings of the two transformers are connected in series, and three output leads are respectively connected to the other sides of the two secondary windings and to the common secondary connection. Direct feedback is provided for each amplifier. Any circuit unbalance is compensated by the insertion of a low value choke in the common transformer secondary connection. Three capacitors are connected across the respective output leads partially to tune the loads, and thereby to nullify to some extent the effects of heavy inductive loads so as to allow operation of the buffer amplifier over a wider range of loads than would otherwise be possible.

Abstract: Disclosed is a bias circuit of an amplifier for a microwave circuit, which amplifier is comprised of a pair of amplifier modules and at least one directional quadrature coupler having four ports including an isolation port, wherein the bias circuit is connected to the isolation port of the directional quadrature coupler.

Abstract: The present linear amplifier uses nonlinear components where an input signal with amplitude and phase variations is concurrently applied to a limiter (41) and an envelope detector (42) which provide signals that serve as a carrier signal and a modulating signal, respectively, to a phase modulator comprising two or more linear suppressed-carrier amplitude modulators (50) connected in cascade. The weighted carrier signal and weighted outputs of the even-numbered amplitude modulators (50.sub.2, 50.sub.4, . . . ) are added separately from the weighted outputs of the odd-numbered amplitude modulators (50.sub.1, 50.sub.3, . . . ) to generate two signals which are combined in a quadrature coupler (56). The two outputs of the quadrature coupler are separately amplified in a pair of amplifiers (60, 61) and combined in a second quadrature coupler (64) to provide a substantially linearly amplified output signal of the input signal.

Abstract: An expander circuit for expanding stereo signals comprises left and right channel variable gain stages whose gain varies in proportion to the amplitude of the control signals fed to the control inputs thereof; and left and right channel expansion control signal providing means for receiving respectively at least portions of the left and right channel signals and feeding expansion control signals to the control inputs of the variable gain stages. These control signals have amplitudes directly proportional to the amplitudes of the signals fed to the inputs of the expansion control signal providing means. The improvement in the circuit is the addition of a signal coupling network for coupling a portion of the left-right channel stereo image producing signal components to the input of the associated expansion control signal providing means and a much smaller porportion thereof to the expansion control signal providing means associated with the other channel.

Abstract: The amplifier includes an audio signal input means and a first pair of integrated circuit audio power amplifiers each having an inverting input and a non-inverting input. The inverting input of one of the first pair of amplifiers is coupled to the input means and the non-inverting input of the other of the first pair of amplifiers is coupled to the input means. A first load has one terminal coupled to the output of one of the first pair of amplifiers and the other terminal coupled to the output of the other of the first pair of amplifiers. A second pair of integrated circuit audio power amplifiers each having an inverting input and a non-inverting input. The inverting input of one of the second pair of amplifiers is coupled to the input means and the non-inverting input of the other of the second pair of amplifiers is coupled to the input means.

Abstract: A priority mixer control for a multi-microphone audio system comprises a threshold signal generator that develops a scanning D.C. threshold signal starting at a maximum level for a time T1 and then decreasing in amplitude as a function of time. Each microphone channel is provided with a control channel including a comparator that compares the microphone signal, as an A.C. signal, with the threshold signal, and that switches the microphone channel to "on" condition when the microphone signal exceeds the threshold; all of the control channels are coupled to a threshold signal restoration means that drives the threshold signal back to its maximum level each time an audio channel is switched "on". An audio channel that has been switched "on" remains "on" for a time T2 substantially longer than the time T1. The number of channels currently in "on" condition is continuously monitored and the output gain is reduced whenever two or more channels are in "on" condition.

Abstract: In a noise reduction system of the type in which an audio signal is delayed in time to permit detection of and reaction to impulse noise before application of the audio signal to a loudspeaker or the like, a transformed version of the audio signal is compared with its time-averaged value, and a resulting detection signal is processed into a control signal with blanking periods that vary as a function of corresponding impulse noise. The detection produces a response to both large impulses which stand out from the audio signal and small impulses which are hidden in the audio signal. The control signal tailors its response to the size of the impulse, blanking the audio signal substantially only for the duration of the impulse. Auxilliary circuitry is provided.

Abstract: A strong electrical signal, occurring at the same time as a relatively wer electrical signal of substantially the same frequency, is suppressed by a method utilizing apparatus wherein (a) the signals are amplified both linearly and non-linearly simultaneously in separate amplifiers, and (b) the outputs of the amplifiers are subtracted from each other while the gain is adjusted in at least one of the amplifiers until the stronger signal is amplified to the same amplitude in each amplifier, leaving the weaker signal isolated as the resultant difference.

Abstract: A noise suppression circuit adapted for use with bifilar windings such as normally present in magnetic pick-up heads. The signals from the windings are coupled to a pair of operational amplifiers having a common gain control resistor for filtering out common mode noise. The first stage amplifiers are coupled to a pair of second stage amplifiers biased at the voltage of the bifilar windings and have resistance-capacitance filter circuits. The second stage amplifiers are coupled to a third stage amplifier which transforms the signal to digital form, the remaining noise appearing as spikes in the signal. The output of this amplifier is coupled to a digital noise filter circuit which includes a one-shot multivibrator coupled to a flip-flop arranged to control the digital waveform so as to filter out the spikes, that is, to eliminate the noise in the signal.

Abstract: The present invention relates to amplifier chains such as are found, for example, in carrier analog transmission by cable with repeaters. Intermodulation noise is reduced by opposing an intermodulation noise generated by a compensation source from the signal available at the chain output to the intermodulation noise generated by the chain. It applies in particular to cable transmission links with repeaters to improve the signal-to-noise ratio thereof.

Abstract: In a feedforward amplifier the balance of the error cancelling loop can be controlled in amplitude and phase by a variable resistor and a variable capacitor connected to the input to the auxiliary amplifier. This can (a) be used for remotely controlled amplifiers to maximize the effect of phase scatter of third order intermodulation vectors, or (b) in a terminal to introduce deliberate distortion to cancel distortion introduced in line amplifiers.

Abstract: Circuitry for dividing radio frequency energy between a plurality of loads is shown in one embodiment to consist of particular printed transmission lines and isolating resistors on a common substrate, each one of such lines forming a path between an input port to which radio frequency energy is applied and a different one of a plurality of output ports to which the loads are connected.Circuitry for amplifying radio frequency energy from a source thereof is shown in the second embodiment to consist of dividing circuitry such as is shown in the first embodiment, a field effect transistor connected to each output port to amplify each portion of the divided radio frequency energy and dividing circuitry such as is shown in the first embodiment, such circuitry being connected in a mirror fashion to the field effect transistors to combine the amplified portions of the radio frequency energy at a single port.The lengths of printed transmission lines in the second embodiment are all equal.

Abstract: An electric amplifier useful for instance in simulators for strong electric signals, comprising several partial amplifiers so connected and voltage fed that they will amplify an interval each of the input voltage. Every partial amplifier comprises at least one amplification component and two gates, of which gates one is blocking those potentials applied to the component that are less than a given first value but is open for potentials exceeding said value while the other gate is open for potentials less than a given second value greater than said first value but is blocking the component for potentials exceeding said second value.

Abstract: The amplifier system comprises a pair of operational amplifiers with an appropriate resistance network such that when a reference voltage and differential signal are applied to the system, changes in the gain of the amplifier system will only change the gain of the differential signal and will not affect the reference voltage.

Abstract: An apparatus for driving a reactive load, comprises a plurality of N multnput elements N .gtoreq. 2, connected in parallel, capable of amplifying a band of frequencies. Two inputs of each element can be connected to sources of direct-current voltage. Each circuit element and elements connected to its inputs define a circuit stage. N means, each means connected to at least one of the inputs of the circuit elements, are capable of equalizing the gain of each of the N stages within a prescribed percentage. A transformer having N primary, input, windings and one secondary output, winding, is connectable to the load. Each of the N primary windings have their inputs connected to one of the inputs of the circuit elements. The transformer is so designed that its impedance, usually inductive, as seen from the load, balances the capacitive load, to be connected to it, over the bandpass of interest.

Abstract: A solid state power combining apparatus for use in a microwave transmission system. The apparatus includes a distributed amplifier having an input transmission line, an output transmission line, and a plurality of amplifiers connected between the input and output transmission lines at quarter wavelength intervals. The phase relationship between the traveling waves placed on the output transmission line from the amplifiers is such that the waves placed on the output transmission line by the amplifiers in the direction toward an output terminal add and the waves placed on the output transmission line by adjacent amplifiers in the direction away from the output terminal cancel each other.Also, a solid state power combining apparatus wherein a plurality of oscillators are connected between input and output transmission lines at quarter wavelength intervals.

Abstract: Improved interferometric amplification is achieved by separating the input signal in accordance with the signal's projection on two orthogonal reference signals, with one of the reference signals capable of following the instantaneous frequency of the input signal. The separated signals are further separated into constant amplitude variable phase signal pairs defining the projected signals, and the constant amplitude signals are amplified and appropriately combined to form a signal that is in an amplified replica of the input signal.

Abstract: This invention relates to amplifiers for producing an accurate amplified version of a low voltage wave form. Specifically, the amplifier of the invention comprises independently fed first and second resistors connected to a common output which feeds a third resistor via a voltage to current converter, the other end of the third resistor being driven from the same point as the first resistor, the ratio of the resistances of the first and second resistors being made equal to the amplification required so that when the low voltage wave form is fed to the second resistor and a wave form approximating to the required output and of slightly higher voltage is fed to the first and third resistors, the voltage at the common output is proportional to the error in the approximated wave form and the voltage thereby developed across the third resistor by the voltage current converter is approximately equal to the error.

Abstract: A plurality of similar power amplifier circuits are connected in parallel in the output of an amplifier between the amplifier's voltage amplifier circuit and the load. Each of these amplifier circuits has a similar ballasting resistor connected between its output and the load. The amplifier circuits have unity closed loop voltage gain. The value of the ballasting resistors is empirically chosen such that these resistors are capable of accommodating differences in the outputs of the amplifier circuits which may occur, such that the load is equally shared between the amplifier circuits.

Abstract: Direct current error signals of either polarity are converted to a unipolar voltage and used to offset a triangular timing wave. The offset wave is applied to threshold amplifier so as to produce pulse width modulated signals. The pulse width modulated signals, together with a polarized direction signal and a clock signal from the triangular wave source, is applied to a servo amplifier containing first and second channels, each containing a flip flop for opening the associated channel in accordance with the polarity of the direction signal so as to pass direct or inverted pulse width modulating signals, respectively, through amplifier and filter circuits to the output terminal. Each of the amplifier circuits has a current sensing resistor, and a switching transistor arranged to switch the associated flip flop and thereby open that channel whenever the current through the sensing resistor exceeds a predetermined level.

Abstract: An audio amplifier which processes mainly dynamic signals and which is provided with a plurality of amplifying systems each having a preamplifier and a main amplifier. A plurality of power sources are used to separately supply electric power to the respective amplifying systems, resulting in elimination of transient crosstalk.

Abstract: An amplifier for an electromagnetic radiation receiver has a plurality of amplification channels for the determination of angular separations, especially for use in self guiding equipment in missiles in which each amplification channel has several amplification stages each of which is of fixed gain. Means are provided to vary the number of operational stages as a function of the sum of the outputs of the channels. A converter is disclosed for converting the analog signal values to stochastic values. A division process is disclosed for the data, based on the use of simple operator and stochastic values.

Abstract: An amplitude stabilized power amplifier having a power splitter for dividing the power of an input signal into a predetermined number of channels, a plurality of amplifier modules for amplifying the power of each of the channels divided by the power splitter, and a power combiner for combining the amplified power signals to provide an amplified output signal. One of the channels of the power splitter is provided with a voltage controlled phase shifter whose phase shift is controlled by an operational amplifier which is responsive to a reference voltage and to the amplified output signal of the power combiner such that the signal in the channel provided with the phase shifter operates to limit the efficiency of the power combiner to maintain a power combiner output signal of constant power with respect to the reference voltage.

Abstract: A transistor power amplifier for transmitting systems, particularly high frequency systems, has two parallel connected signal paths each of which is fed with the input signal. In a first of the signal paths, a 6 dB attenuator connects the input to the input of an amplifier and a fraction of the output of the amplifier is connected to one input of a correction amplifier, constructed as a differential amplifier. In the other signal path a delay member which simulates the delay of the first amplifier connects the circuit input to another input of the correction amplifier. The correction amplifier therefore is provided with a fraction of a delayed amplified signal which is subjected to error and includes an error component and with the delayed original input signal and emits a control signal for a second amplifier in which the error component produced in the first amplifier is contained in a double and inverted magnitude.

Abstract: A circuit arrangement for combining high frequency power components with the same frequency which come from amplifiers or generators and are fed to a 90.degree. parallel circuit bridge having two substantially decoupled inputs with the input resistance values of these inputs depending on the output load. The operating voltage supplies of the amplifiers or generators are separately controllable and are controlled so that the output powers of these amplifiers or generators, respectively, remain substantially constant even with mismatching.

Abstract: In differential input DC gain amplifiers with high input impedance, a capacitive attenuator is built-in in order to reduce the amplifying effect on the AC component due to interference by the industrial power lines. Such attenuation is obtained by feeding back through cross capacitors the AC signal at one output to the input on the opposite side so that the ratio of the differential outputs to the differential inputs for the AC component is substantially unity.

Abstract: A novel microwave power divider is disclosed that is a combination of an ort junction circulator and a novel isolator-mismatch device for each circulator port other than one input port and divides microwave signal power incident to the input port into any desired ratio among the output ports and isolates all the ports from microwave power reflected back toward the divider after being propagated through the divider and thus prevents interaction among line devices, e.g. amplifier units, that are fed by the output ports. Also a novel microwave power combiner is disclosed that is a combination of an N-port junction circulator and a novel isolator-reflector device for each port other than one output port to combine at the one output port identical microwave signals or microwave signals that differ in frequency or phase incident to the isolator-reflector devices. The microwave power combiner, like the microwave power divider, provides isolation among the signal transmission lines.

Abstract: In an analog data acquisition system, used for digital treatment, analog signals of different levels received from remote locations are amplified with a selected gain before being converted by a common A/D converter. A discretely variable gain amplifier is used in which a series of programmed predetermined ranges are sequentially tested against the capability of the A/D converter in relation to the particular input analog signal. The first acceptable gain is selected and a code can be used to identify the selected gain for digital treatment of the derived corresponding digital signal.

Abstract: An active dual channel tuning control particularly useful for television and stereo applications has two independently adjustable channels. For example, each channel for stereo has an input for receiving a decoded signal which represents the left or right channel information. Each channel additionally has a feedback amplifier with an adjustably turned output to permit highly selective tuning and impedance matching to the following amplification stages. Switching networks are provided for reversing the channel outputs as well as for selectively inhibiting either of the channel outputs in either the normal or reversed channel condition.

Abstract: A plurality of luminescent elements, such as light-emitting diodes, incandescent lamps or the like, are located adjacent each other, each connected to the output of a difference amplifier. The respective inputs of the difference amplifier are connected, on the one hand, to a voltage divider to have different reference voltages applied thereto and, on the other, in common to the input voltage to be sampled so that, as the voltage changes between the amplification ranges of the difference amplifiers, the output therefrom will change in accordance with input voltage so that the brightness of the respectively connected luminescent elements will also change, thus providing gradual increase in brightness of any individual element as the voltage changes. The difference amplifiers may be differentially connected operational amplifiers.

Abstract: A dynamic expander which is particularly suitable for restoring the original dynamic range of prerecorded stereo sound program material is disclosed. In this embodiment, the expander comprises first and second variable gain amplifiers respectively coupled to a stereo input. The gain of the amplifiers is controlled by a common slow-attack, slow-decay time-constant circuit. An input of the time-constant circuit is coupled to the stereo input and the time-constant circuit responds thereto to provide a control signal which is indicative of the volume of the program material but which varies in accordance with the characteristics of a non-linear element in the time-constant circuit and with the slow-attack and slow-decay characteristics of the time-constant circuit. The control signal of the time-constant circuit drives a light-emitting-diode (LED) which, in turn, determines the resistance of a pair of matched, light-controlled-resistors (LCR's).

Abstract: An electrical musical instrument amplifier is disclosed in which a signal which has been provided by an instrument to a second one of two different preamplifiers for amplification therein is passed to one of the inputs of a summing amplifier together with the output of the first preamplifier, the output of the summing amplifier being coupled through a tube driven power amplifier to a loudspeaker system. The amplified signal from the second preamplifier is applied to a second input of the summing amplifier via a circuit arranged as a voltage divider and having a variable resistance provided by a field effect transistor driven by an oscillator. The modulation provided by the field effect transistor and associated oscillator can be adjusted to provide total phase reversal as well as amplitude modulation when combined with the signal at the output of the second preamplifier, to provide a tremolo or vibrato effect.

Abstract: A distortion-free amplifier for electric signals has a high-quality low-power amplifier-section. In addition there is a high-power amplifier-section which delivers the majority of the current to the load. A feedback signal is derived which is a measure of the output current of the high-power section and not the low-power section. The feedback signal is applied to the inputs of both amplifier-sections negatively in an amount such as to remove from the combined output currents in the load any distortion occurring in the contribution from the high-power section.

Abstract: An automatic level control circuit utilizes digital techniques in the gain control loop to maintain an output signal within a predetermined amplitude range. A comparator circuit, which has preselected limits or threshold levels that establish the predetermined amplitude range, produces a hysteresis property in its operation. The hysteresis provides a substantial improvement in noise immunity over conventional automatic gain control circuits. The output of the comparator is applied to digital circuitry which controls the variable gain of a linear amplifier. The digital circuitry also includes a preset circuit which sets the gain of the variable amplifier to the middle of its range, thereby reducing the average time required for an input signal to produce an output signal within the predetermined range.

Abstract: An edge-guided mode microstrip device similar to an edge-guided mode isolr having opposed straight and tapered edges along which microwave energy is adapted to travel with the exception that in the subject invention the thickness of the ferrite substrate underlying one tapered edge is abruptly changed in order to obtain mismatch thereat causing energy traveling along said one tapered edge to be reflected back along the same edge to the port whence it came. Coupling a microwave power amplifier to a port of a microwave circulator by means of a respective power reflector according to the subject invention provides a simple yet effective power combiner for microwave signals.